Bag sealing machine



June 20, Q T. HAYES BAG SEALIN MACHINE Filed July 5l, 1937 s sheetssheet 1 qllm -- www mw INVENTOR ATTORNEYS o u n o o o o C. T. HAYES BAG SEALING MACHINE June 2o, 1939.l

Filed July 31, 19575 ATTORNEYS `lune 20, 1939. c. T. HAYES BAG SEALING MACHINE 3 Sheets-Sheet 3 Filed July 51, 1957 INVEN-ron AfroRNlaYSA Patented June 20, 1939 PATENT OFFICE nacL sEAuNc. Y MACHINE Charles T. Hayes, Richmond, Va., assignor to James River Paper Products, Inc.,- Richmond, Va., a corporation of Virginia Application VJuly 31, 193'1, Serial No. 156,799

18 Claims.

To seal the end of a paper bag so that it will be impervious to leakage of gases and liquids requires more than the momentary I pressure which can be applied to it in the interval between bags produced on a high-speed bag-forming machine. One object of the present invention is to provide a sealing machine having a high output combined with application of pressure for an adequate time to seal the bag perfectly.

A particular object is to provide ar sealing machine which can take the output of a bag-forming machine and still apply to each bag pressure for a sumcient time to effect a perfect seal. Another object of the invention is to providea bag-sealing machine capable of reactivating thermoplastic adhesive and at the same time applying pressure to seal the bag.

Another object is to provide a mechanism for the transfer of bags from a bag-forming machine to a sealing machine.

Another object is to provide a bag-sealing machine capable of applying a gradually increasing pressure tothe parts of the bag to be sealed together.

Further objects will appear from the detailed description of the invention which follows. Reference will be' made in this description to an illustrative form of the invention shown in the accompanying drawings, wherein Fig. 1 is a side elevationy of a .bag-sealing machine and transfer mechanism in accordance with the invention, with parts broken away to reduce the size of the figure;

Fig. 2 is a vertical section on the line 2-2 of Fig. 1;

Fig. 3 is a detail section on the line 3`3 of Fig. 2; y

Fig. 4 is a detail section on the line 4-4 of Fig. 2;

Fig. 5 is a. detail section on the line 5-5 of Fig. 2;y

Fig. 6 is a perspective view of one portion of the conveyor and its controlling mechanism;

Fig. 'I is a central section of one end of the 45 conveyor and the transfer mechanism, taken parallel to the path of travel of the bag;

Fig. 8 is a perspective view of the transfer flap; and

Fig. 9 is a detail sectional view illustrating the transfer mechanism and clamp in a different position from that shown in Fig. 7.

The machine illustrated in the drawings is designed to seal the ends of bags by means of thermoplastic adhesive previously coated on the bag and hardened. An example of a bag particularly adapted to be sealed on this machine is shown in Haskell Patent No. 1,983,291. 'I'he adhesive lshould be present in suflicient thickness to provide a body capable of flowing under the application of heat and pressure into the folds and cor- 5 ners of the bag.

The bag-sealing machine comprises an endless conveyor 2travel1ing upon sprockets 4 and 6 mounted upon shafts 4a and 6a respectively, journalled in bearings 8 and I8. These bearings are 10 mounted upon a frame i2 and the bearings I0 can be adjusted longitudinally of the frame by a screw I4 and( clamped in position by screws I6. 'I'he conveyor is formed of two chains I8 and 20 connected together at intervals by clamps 22., -15 which will presently be described in detail. The upperspan of the conveyor is supported by rails 24 and the lower span by rails 26.

Each clamp comprisesa lower jaw 28 and an upper jaw 30. The lower jaw is connected to 30 the chains i8 and 20 by bolts 32 which form extensions of two adjacent pins of the chains. The upper jaw is guided between cheeks 34 of the lower jaw and its vertical motion is limited by headedscrews l36 which screw into the upper 25 jaw and are slidably guided in holes 38 of the lower jaw. Surrounding each screw 36 is a spring 48, these springs normally holding the jaws apart. The lower jaw is faced with a rubber vcushion 42 held in a channel bar 44 attached by screws 46 3 to the lower jaw. 'Ihe upper jaw is bored to receivea heating element 48, which receives current through wires 58 in a manner to be described presently. At the ends of the lower jaw 28 are blocks 52 rabbeted to fit over the rails 24 so as 35 to be guided thereby.

Standing up from the framel l2 are bridges 54 comprising upright legs 58 and crossbars 58. Cam rails 60 are mounted upon the legs 56 by screws 32 fitting through elongated slots 64 in 40 the cam rails and screwing into the legs 5 6. The heads of the screws 62 hold-the cam rails 80 against lateral motion, but allow the rails to move up and down guided by the Shanks of the screws. The cam rails rest upon rolle'rs 86 jour- 45 nailed upon pins 68 projecting from the ends of the upper jaw 38 of each clamp 22. The cam rails 60 may be held up by springs (not shown) attached to them and also by the springs 0 of the clamps. Extending across the bridges 54 are 50 shafts 18, to which are fixed cams 'l2 acting against the upper side of cam rails 60. A handwheel 18 is fastened upon one shaft 'lli and this shaft is connected by sprocket wheels 18,'18 and a chain -to the other shaft 18. Thus rotation l5 30' chine.

of the handwheel '|4 causes the shafts 18 to turn in unison and the cams 12 to bear in unison against the cam rails 68. When the cams 'l2 are turned down the cam rails 88 press the upper 5 jaws of the clamps 22 down against the lower jaws. When the cams 12 are turned up thecam rails release the upper jaws of the clamps and allow the springs 48 to separate them from the lower jaws. When the cams 12 are turned down and the conveyor is travelling in counterclockwise direction, the clamps are open as they travel along the bottom and are closed as they are engaged by the downwardly turned ends 82 of the cam rails 88. It is just prior to the closure of the 15 clamps at this point that the bags are fed in by a transfer mechanism to be described presently. If for any reason itis necessary to stop the travel of the conveyor the cam rails 88 can be raised immediately to allow the clamps to open and release the bags, so that they will not be charred by the heated clamps. The cams '|2 are secured to shafts 10 by set screws 84 passing through their hubs 86. By adjusting the cams 12 on the righthand shaft 18 of Fig. 1 so that they do not turn down quite so far as the cams on the left-hand sure becomes suilciently heavy to force the adhesive into the minutest cracks and folds of the bag. The rubber facing of the lower jaw enables the jaw to adapt itself to different thickness of paper at different parts of the bag.

The wires 58 leading to the heating element 48 of each clamp are connected to a brush box 88 having brushes 98 which bear against conductor bars 92 mounted upon insulating supporting bars 84 suspended by brackets 98 from the bottom of rails 24. Preferably the heating elements of all the clamps are connected together, as indicated by wires 98 of Fig. 6, so that it is only necessary for the conductor bars 92 to extend over a distance slightly longer than the space between two of the clamps. In this way the brush box 88 at- 0`tached to each clamp will in turn take up the supply of electricity from the conductor bars to all the heating elements. The conductor bars and their support are curved away from the brush boxes at the lright end to allow the brushes to feed on to the conductor bars smoothly.

The transfer of the bags from the bag-forming machine (not shown) to the bag sealing machine is accomplished by the mechanism shown in outline in Fig. 1 and in detail in Figs. 7, 8 and 9. A

drum |88 corresponds to the bottom closing drum of the ordinary bag machine, but in this case it does not serve to seal the bottoms of the bags. The bottoms of the bags are tucked by tucker bars |82 on a drum |84 behind clamps |88 on the drum |88. The bags are drawn by the clamps I past an idler roller |88 and there released from the clamps in the' usual way. A band ||8 travelling over drum |88 and idler rollers |2 and 4 conveys the bags to and partly around another drum H6. The drum ||8 is rigidly connected to a gear ||8 meshing with a gear |28 rigidly connected with sprocket wheel 4 of the bag-sealing machine, so that the roller IIS rotates with the same peripheral 'speed as the sprocket 4. The

roller H6 is recessed at |22 and |24 to receive the clamps 22 as they pass. Below'the drum H8 is rotatably mounted a shaft 28 which carries the idler roller H2 loosely upon it and besides has fixed to it a transfer flap |28. This flap is arranged to swing from the dotted line position |29a to the full line position |28 through the action of a cam |38 xed to the shaft |32 of drum H8. This cam bears against a roller |33 on a lever |34 which swings on a fixed pivot |38 and has connected'to its lower end a link |38. The other end of link |38 is articulated to an arm |48 xed to shaft |28. Thus for each half revolution of drum H8 the cam |38 swings the flap up to full line position and down to dotted line position. This swing is coordinated with the travel of the clamp which is passing at the time so that just as the clamp reaches the proximal position shown in Fig. 7 the flap, which is moving somewhat more rapidly, swings up from the position shown in Fig. 9 and thrusts the projecting end of the bag between the open jaws of the clamp. Shortly after, as the bag continues to move upward with the drum ||8 and the clamp 22, the cam 82 engages the rollers 86 of the upper jaw of the clamp and presses the upper jaw down against the end of the bag.` The end of the bag being supplied with a hardened thermoplastic adhesive, as the heat and pressure continues, the thermoplastic melts and flows into a continuous body penetrating the smallest cracks and folds of the bag end.

The drive for the drums H8 is derived from a gear |58 through an intermediate gear |52 meshing with gear ||8. The drum |88 is driven by a gear |54 xed to it and meshing with gear |88.

It will be seen that I have-described a machine capable of taking bags from a bag-forming machine as fast as they are formed, holding them by clamps, which maybe heated, for any desired length of time, depending upon the length of the conveyor and cam rails 82, and nally releasing the bags as the clamps are opened at the end of the cam rails.

Having described my invention, I claim:-

l. In a bag sealing machine, an endless conveyor, a series of clamps on said conveyor,veach comprising a pair of parallel jaws arranged transversely on said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, means for closing said jaws and holding the same closed during a portion of the travel .of said conveyor, and means for feeding a bag between each pair of jaws just prior to its closure.

2. In a bag sealing machine, an endless conveyor, a series of clamps on said conveyor, each comprising a pair of parallel jaws arranged transverselyon said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, cam bars mounted adjacent said conveyor in position to engage the jaws of said clamps in their travel and to hold the jaws closed during a portion of their travel, and means for feeding a bag between each pair of jaws just prior to its closure.

3. AIn a bag sealing machine, an endless conveyor, a series of clamps on said conveyor, each comprising a pair of parallel jaws arranged. transversely on said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, cam bars mounted adjacent said conveyor in position to engage the jaws of said clamps in their travel .and to hold the jaws closed during'a portion of their travel, said cam bars having a gradual slope 75 so as to increase their pressure on said clamps gradually, and means for feeding a bag between each pair of jaws just priorto its closure. e 4. In a bag sealing' machine, an endless conveyor, a series of clamps on said conveyor, each comprising a pair of parallel jaws arranged transversely on said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, cam barszmounted adjacent said conveyor in position to engage, the jawsl of said clamps in their travel and to hold the jaws closed during a portion of their travel, said cam bars being independently adjustable at their opposite ends in order to va'ry their position with respect to the path of travel of said clamps,` and means for'feeding a bag between each pair of jaws just prior-to its closure.

5. In a bag sealing machine, an endless conL veyor,' a series of clamps on said conveyor, each comprising a pair of parallel jaws arranged transversely on said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, cam bars mounted adjacent said conveyor so as to be movable toward and away from the conveyor,

'means for so moving said cam bars; said cam bars,

when nearest to said conveyor, being adapted to engage the jaws of said clamps in their travel and to hold the jaws closed during a portion of their travel, meansfor heating said clamps, and means `for feeding a bag between each pair of jaws just prior to its closure.

6. In a bag sealing machine, an endless conveyor, a series of clamps on said conveyor, each comprising a pair of parallel jaws arranged transversely on said conveyor and having a limited relative movement to open and close the clamp, springs normally holding said jaws apart, cam bars mounted adjacent said conveyor so as to be movable toward and away from the conveyor, a plurality of cams adapted to bear at different points upon said cam bars to move the same, means for operating said cams simultaneously; said cam. bars, when nearest to said conveyor, being adapted to engage the jaws of said clamps in their travel and to hold the jaws closed during a portion of their travel; means for heating said clamps, and means for feeding'a bag between each pair of jaws just prior to its closure.

"l. In a bag sealing machine, a conveyor, a series of clamps on said conveyor, electric heating elements in said clamps, slide conductors mounted parallel to the conveyor, brushes travelling on said conductors and connected with said heating elements, means for opening and closing said clamps, 'and means for feeding bags to said clamps just 8. In a bag sealing machine, a conveyor, a series of clamps on said conveyor. electric heating elements in said clamps, conductors connecting said heating elements together, slide conductors mounted parallel to the conveyor, a plurality of sets of brushes mounted at spaced points on said conveyor and bearing on said slide conductors, means connecting said brushes with said heating elements, said slide conductors being shorter than the length of the conveyor: but longer than the distance between two sets of brushes, means for opening and closing said clamps, and means for feeding bags to said clamps just `prior to their closure.v y

9. In a bag sealing machine, an endless conveyor, a series of clamps mounted transversely on said conveyor, each clamp comprising a pair of jaws. one of said jaws being composed of metal having a yielding face, means whereby said jaws are held apart during a portion of the conveyor travel and are held closed during another portion of the conveyor travel, and means for feeding bags to said clamps just prior to their closure.

10. The combination with a bag sealing machine comprising a travelling conveyor having clamps thereon to grasp and seal the bags, of a drum adjacent said conveyor, a conveyor band cooperating with said drum tofeed the bags toward said clamps and a guide iiap adapted to engage each bag as it emerges from said conveyor band to guide it into one of said clamps.

11. The combina-tion with a bag sealing machine comprising a 'travelling vconveyor havingl clamps thereon to grasp and seal the bags, of a drum adjacent said conveyor, a conveyor band cooperating with said drum to feed the bags toward said clamps and a pivoted guide flap adapted to engage each bag as it emerges from said conveyor band, said guide ap normallystanding out of the path of said clamps, and means to swing said guide flap in behind each clamp as it passes to guide the bag into the clamp.

12. In a bag sealing machine, an endless conveyor comprising a pair of continuous flexible members joined at intervals by rigid cross members, each cross member having associated with it a bar normally held apart from said cross member by springs, but movable into contact with said cross member to act as a clamp for clamping bags to be sealed, and means for moving said bar into contact with said cross member at a certain point in the travel of said conveyor.

13. In a bag sealing machine, an endless conveyor comprising a pair of continuous flexible members joined at intervals by rigid cross members, each cross member having associated with it a bar normally held apart from said cross member by springs, but movable into contact withA said d cross member to act as a clamp for clamping bags to be sealed, stationary guide bars on which said cross members travel, and cam bars adapted to be engaged by said bars in their travel to force the same into contact with said cross members and to maintain said contact during a predetermined length of travel of said conveyor.

14. In a machine for sealing bags by thermoplastic adhesive previously hardened on the bag material, clamping means having opposed pres--4 said jaws, and means operating in synchronism with said feeding means for pressing said jaws together, first with a light 'pressure and then with a gradually increasing pressure. v

16. For use in combination with a bag machine adapted to convert a continuously travelling sheet of paper into a tube and to sever the tube into bag lengths, a bottom sealing mechanism adapted to receive the bag lengths as they are delivered from the bag machine and to reactivate a thermoplastic adhesive previously applied to the bottom of the bag length and to seal the bagbottom by pres- 17. In a bag sealing machine, a conveyor, a.

series oi.' clamps on said conveyor, electric resistance elements mounted in heat transmitting relation on said clamps, means for transmitting electrical energy to said resistance elements from a stationary source, means for opening and closing said clamps, and means ior feeding bags to said clampsjust prior to their closure.

18. For use in combination with a bag machine adapted to convert a continuously travelling sheet of paper into a tube and to sever lthe tube into bag lengths. a bottom seallns mechanism adapted to receive the bag lengths as they are delivered from the bag machine comprising an endless conveyor, a series oi' clamps on said conveyor, a pivoted flap adapted to engage each bag length as it is delivered from the bag machine. said ilap normally standing out of the path ot said clamps, and means to swing said guide ap in behind each clamp as it passes, "to guide the bag into the clamp.

CHARLES T. HAYES. 

